<?xml version="1.0"?>
<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100">
  <rect width="100" height="100" fill="blue">
    <animate attributeName="fill"
      begin="999999999999999999999999999999999999999999999999999999999999999999999999999999999"
      dur="5s" from="blue" to="red" repeatCount="indefinite" additive="sum"/>
  </rect>
</svg>
